• 무역상무연구
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• 제58권
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• pp.237-263
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• 2013

Traditionally, a L/C (letter of credit) has been known as a relatively low risk method of payment. This is why L/C has been used in international trade. However, L/C has a number of weak points such as high cost, long processing time, and complicated documents. Using an electronic L/C is one way to solve those weak points. In Korea, there are two types of electronic L/C. One is the EDI (Electronic Data Interchange) based L/C and the other one is the XML (Extensible Markup Language) based L/C. The former, established in 1990's, is sent from banks to the beneficiary solely through VAN (Value Added Network, KTNET) operators. On the other hand the latter, started in 2005, is sent from banks to KFTC (Korea Financial Telecommunications & Clearings Institute) for management of the L/C balance, as well as to KTNET. So far, paper L/C and EDI based L/C have been used overwhelmingly instead of XML based L/C in spite of the aforesaid disadvantages. In this paper, the authors examined empirically why the users of electronic L/C were reluctant to use XML based L/C. The results are as follows. First, the users of paper L/C were more dissatisfied than the users of electronic L/C due to many factors such as cost, the time required, and information reuse. Second, the users who have more experience with XML based L/C wanted to adopt integrated management with EDI based L/C more than the users who had not experienced XML based L/C. Third, the users who had used more than one form of L/C wanted to adopt integrated management to EDI and XML based L/C more than the users who had only used one form of L/C. Therefore, the authority for electronic L/C should consider a change of the policy from the XML based electronic L/C oriented to integrated management of the various types of L/C.

• 한국결정성장학회지
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• 제3권2호
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• pp.125-130
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• 1993

수직 2단 전기로를 제작하고 결정성장관에 꼬리관을 연결하여 seed 결정없이 승화 방법으로 CdS 결정을 성장하였다. 이때 시료부분과 성장부분의 온도차 ${\Delta}T$가 이론적인 값 $14.7^{\circ}C$와 비교해서 실험적으로 얻은 값이 $15^{\circ}C$ 로 아주 일치하는 값을 나타내었다. 이때 꼬리관의 온도를 $110^{\circ}C$로 시간당 0.38mm 정도로 빨리 결정성장관을 끌어 올려 결정을 성장하였다. 분말법의 X-선 회절무늬와 Laue 배면 반사법의 Laue 무늬로부터 성장된 결정이 육방정이고 결정성장관의 길이 방향으로 c축을 갖는 단결정임을 확인하였다. 또한 CdS 단결정은 상온에서 전자 이동도와 운반자 밀도는 각각 $316cm^2/V{\cdot}sec$와 $2.90{\times}10^{16}cm^{-3}$정도이였다.

• 한국축산식품학회지
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• 제25권3호
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• pp.350-356
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• 2005

Probiotics로서의 활성이 높은 Lactobacillus acidophilus 30SC의 생존성을 증진시키기 위한 기초 자료를 얻고자, heat shock stress를 가한 후 생균수를 측정하고, 생존율의 변화를 통해 고온 처리에 의한 고온 및 냉동 내성의 증진 효과를 평가하였다. 또한 열처리 동안 새로이 발현되는 단백질을 1차원 및 2차원 전기영동을 이용하여 확인하였으며, 주사전자현미경을 사용하여 세포 모양을 관찰하였다. L. acidophilus 30SC는 $55^{\circ}C$의 heat shock stress를 받았을 때 생존 균수가 감소하는 것으로 나타났다. 나머지 처리구는 $37^{\circ}C$에서 계속 배양한 것과 별다른 차이를 나타내지 않았다. 특히 $45^{\circ}C$로 heat shock stress를 준 경우 $37^{\circ}C$에서 배양한 것과 거의 동일하였다. L. acidophilus 30SC에 $45^{\circ}C$로 heat shock stress를 가한 뒤 추가로 55 및 $60^{\circ}C$에 노출시켰을 때 가장 높은 생존율을 나타냈고, 치사 수준인 $55^{\circ}C$의 heat shock stress를 받은 후 $55^{\circ}C$ 및 $60^{\circ}C$에 노출되었을 때 생존율이 급격히 감소하는 경향을 보였다. L. acidophilus 30SC에 $55^{\circ}C$로 15분 Heat shock stress를 준 경우 약 22와 25 kDa의 단백질들이 새로이 발현된 것으로 나타났으나, 24와 27 kDa로 추정되는 단백질의 발현 정도는 낮았음을 확인하였다. 2차원 전기영동을 실시한 결과, $37^{\circ}C$에서 배양한 대조구와 비교할 때 $55^{\circ}C$로 heat shock stress를 준 경우 새로이 5개의 protein spot을 발견할 수 있었다. 주사전자현미경으로 세포의 형태를 관찰한 결과 heat shock stress를 준 경우에는 세포의 길이가 신장되는 경향을 나타내었다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1996년도 춘계 학술대회지
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• pp.64-65
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• 1996

• 한국미생물·생명공학회지
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• 제31권1호
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• pp.69-74
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• 2003

천연 식물 재료를 이용한 여드름 개선제 개발을 위해 솔잎, 오미자, 에탄올 추출물의 여드름 원인균으로 알려진 Propionibacterium acnes, Staphylococcus epidermidis와 Malasseizia furfur에 대한 증식억제 효과를 검토한 결과 여드름 원인균 3종류 모두에 항균력을 나타내었다. 오미자. 솔잎의 M. furfur에 대한 성장억제효과는 초기배양시 균의 억제효과가 뚜렷하게 나타났으며, 오미자의 경우 모든 농도에서 $10^1$CFU/mL 이하 또는 사멸하는 경향을 나타내었다. S. epidermidis에 대한 오미자, 솔잎이 높은 성장억제효과를 보였으며, 0.12% 이상일 때 강한 항균효과를 나타내었다. P. acnes의 성장은 솔잎, 오미자를 0.06% 이상 첨가한 경우 배양 1일째 모두 사멸하여 매우 높은 항균활성을 나타내었다. 솔잎, 오미자의 생육억제효과는 여드름 원인균 중 P. acnes가 가장 강하게 나타났고, M. furfur, S. epidermidis 순이었다. 각 천연물의 여드름 원인균에 대한 최소저해 농도를 측정한 결과, P. acnes의 MIC는 0.075 mg/mL로 가장 낮게 나타났고, M. furfur는 0.6-l.8 mg/mL, S. epidermidis에 대해 1.2%-l.8mg/mL으로 높게 나타났다.$ 80^{\circ}C$, $100^{\circ}C$에서 30분 동안, 121$^{\circ}C$ 15분 열처리한 오미자와 솔잎 추출물의 여드름 원인균에 대한 항균효과는 가열 온도가 증가함에 따라 다소 감소하였으나 추출물의 항균활성에는 뚜렷한 영향을 미치지 않았다.

• 한국산학기술학회논문지
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• 제18권5호
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• pp.667-673
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• 2017

본 연구는 그라비올라 (Graviola; Annona muricata Linn.) 잎의 항균소재 개발 목적으로 병원성 세균에 대한 항균효과를 검증하기 위해 시행된 실험 연구이다. 그라비올라 잎의 추출 온도를 $60^{\circ}C$, $80^{\circ}C$, $98^{\circ}C$ 달리하여 열수 추출하여 수율 및 추출 조건을 찾았으며 실험 균주 S. epidermidis, S. aureus 및 E. coli TOP 10에 대한 항균 활성은 한천 배지 확산법으로 평가하였다. 추출 온도 $60^{\circ}C$, $80^{\circ}C$, $98^{\circ}C$에서 3.02%, 14.73%, 20.76% 수율을 얻었고, S. epidermidis, S. aureus 및 E. coli TOP 10에 대한 항균 활성은 S. epidermidis에서 항균 활성이 나타났으며 $98^{\circ}C$에서 추출한 그라비올라 잎 시료 중 200 mg/mL에서 13 mm, 500 mg/mL에서 20 mm 투명환이 나타났다. MIC는 100 mg/mL이다. 추출 온도, 농도가 높을수록 우수한 성장억제효과를 확인하였다. 위 결과로 천연물속에 함유되어 있는 천연 항균 성분이 피부 상재균에서 우수한 항균력은 앞으로 피부미용 기초자료와 화장품 소재로서의 활용 가능성이 높을 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권10호
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• pp.1461-1468
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• 2014

This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, $135{\mu}g/mL$. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of $306{\mu}g/mL$ and $183{\mu}g/mL$, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% ($EC_{50}$) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and $47.8{\mu}g/mL$, respectively. Flavonoid content of methanol extracts in S. grandiflora L. T was $22.5{\mu}g/mL$ and the highest among plant extracts tested. These results indicated that C. aurantifolia Swingle, S. grandiflora L., P. sarmentosum Roxb, and C. domestica Valeton have antibacterial and antioxidant activities and can be used as alternative antibiotics or potential feed additives for the control of animal pathogenic bacteria.

• 제어로봇시스템학회논문지
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• 제17권3호
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• pp.283-288
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• 2011

In this paper, an adaptive signal tracking loop for a GPS L1/L2C/L5 receiver is designed. The design parameters is adjusted according to the receiver's operating conditions such as the signal strength and the receiver dynamics by using the different characteristics of GPS L1, L2C and L5 signal. Simulation results show that the tracking accuracy of the proposed signal tracking loop is better than those of L1, L2C and L5 only signal tracking loop.

• 대한기계학회논문집A
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• 제26권3호
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• pp.521-527
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• 2002

In this paper, tensile behavior and low cycle fatigue behavior of 316L stainless steel which is currently favored structural material for several high temperature components such as the liquid metal cooled fast breeder reactor (LMFBR) were investigated. Research was performed at 55$0^{\circ}C$, $600^{\circ}C$ and $650^{\circ}C$ since working temperature of 316L stainless steel in a real field is from 40$0^{\circ}C$ to $650^{\circ}C$. From tensile tests performed by strain controls with $1{\times}10^{-3}/s,\; l{\times}10^{ -4}/s \;and\; 1{\times}10/^{ -5}/ s $ strain rates at each temperature, negative strain rate response (that is, strain hardening decreases as strain rate increases) and negative temperature response were observed. Strain rate effect was relatively small compared with temperature effect. LCF tests with a constant total strain amplitude were performed by strain control with a high temperature extensometer at R.T, 55$0^{\circ}C$, $600^{\circ}C$, $650^{\circ}C$ and total strain amplitudes of 0.3%~0.8% were used and test strain rates were $1{times}10^{-2} /s,\; 1{times}10^{-3} /s\; and\; 1{times}10^{-4} /s$. A new energy based LCF life prediction model which can explain the effects of temperature, strain amplitude and strain rate on fatigue life was proposed and its excellency was verified by comparing with currently used models.

• 한국의류산업학회지
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• 제17권4호
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• pp.635-645
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• 2015

This study analyzed the range of motion of upper body in different configurations of firefighters' protective clothing and equipment. The purpose of this study was to understand the influence of firefighters' protective clothing and equipment over upper body motion in order to improve design of firefighters' protective clothing and equipment. 12 firefighters' upper body range of motion was analyzed while performing standing and walking trials in five different garment configurations including turnout ensemble, fire boots and the self-contained breathing apparatus. Analysis of upper body range of motion included spinal joints of L5S1, L4L3, T1C7, and C1Head. During standing trials, garment configurations caused a significant difference in range of motions at joints of L5S1, L4L3, T1C7, and C1Head. Analysis on the mean of range of motions at L5S1 and L4L3, showed that firefighters' waist bent forward significantly to a greater extent while they wore a self-contained breathing apparatus. A significantly increased range of motion was found for T1C7 and C1Head while carrying a self-contained breathing apparatus, which indicated an increase in the extension of the trunk and neck backward to stand upright and look squarely. A significant difference in range of motion was also found for L5S1 and L4L3 during walking trials.